1. Field of the Invention
The present invention relates generally to a ballast water treatment device and, more particularly, to a ballast water treatment device which includes a filtering unit filtering ballast water introduced into a ship using a filter, a vortex generating unit generating an artificial vortex in the ballast water filtered by the filtering unit, and an ultraviolet treatment unit having an ultraviolet lamp which sterilizes the ballast water discharged from the vortex generating unit using ultraviolet rays, thus preventing secondary contamination resulting from by-products, preventing a ballast tank from becoming contaminated, affording effective maintenance, and making it convenient to control, and in which an artificial vortex is formed in the ballast water when it is mixed, thus allowing a large quantity of ultraviolet rays to be radiated onto the ballast water passing through the ultraviolet treatment unit, therefore improving a sterilization effect.
2. Description of the Related Art
After goods are unloaded from a ship, the ship does not rest sufficiently deep in the water, so that it is apt to lose its balance. Further, a propeller or the like is not sufficiently immersed in the water, so that the propeller does not operate efficiently. Thus, in order for the ship to maintain its balance while sailing without goods, seawater is put into a tank of the ship. Such seawater is called ballast water. The increasing volume of internal trade has led to an increase in the ratio of marine transportation using a ship that can transport a large amount of goods, and the size of the ship also has been increasing rapidly. Thus, the volume of ballast water used in the ship is also increasing considerably. As the volume of the ballast water used in the ship increases, the damage done to the endemic marine ecosystem resulting from it being attacked by exotic marine organism species is also increasing. In order to solve the international environmental contamination problem, the Internal Maritime Organization (IMO) completed the ‘International treaty concerning control and management of ballast water and sediment of ships’ in 2004, which is effective from 2009.
As a conventional method of treating ballast water, a land treatment method was used but is ineffective. Thus, a method of installing a ballast water treatment system in a ship has been widely used. The ballast water treatment system mainly uses filtering, heat treatment, chemical treatment, electrolysis, ozone treatment or ultraviolet ray radiation, etc.
However, the heat treatment is problematic in that it is difficult to treat microorganisms or inorganic sources of contamination which are resistant to heat. The chemical treatment is problematic in that secondary contamination may occur after ballast water has been treated. Further, the electrolysis or ozone treatment is problematic in that an explosion may be caused by a short circuit and it is inefficient to manage. Especially, the filtering is problematic in that sediment must be removed from a filter and the operation of treating ballast water must be halted when the sediment is being removed. Further, the ultraviolet ray radiation is problematic in that its efficiency is low because of foreign substances adhering to the surface of a sleeve which surrounds an ultraviolet lamp. Furthermore, when each of the above methods is individually used, it is difficult to completely treat ballast water. Meanwhile, if all of the above methods are used together, treatment is expensive, so that it is inefficient.